Wildlife and bird anatomy Flashcards
(95 cards)
Describe the structures of the head in birds ?
The head of birds is divided into three parts
- neurocranium, splanchnocranium and mandibular
Neurocranium
- single occipital condyle
- very large occipital sockets, good vision
- many sinuses which makes birds prone to infection
Splanchnocranium
- Forms the upper (maxillary) jaw and upper roof of the oral cavity
- includes incisive bone holding upper beak with rod like “pushrods” structure
Mandible
- Consist of two thin bones which are fused rostrally and covered by lower beak
- connect to the skull bewteen quadrate bone and articular bone.
Describe how musculoskeletal system is adapted for flight in birds ?
Adaptation of the musculoskeletal system of birds for flight.
- pneumatice bones
- bone fusions of the appendicular skelton (pectoral limb and wing) providing rigidity and strength
- strong pectoral girdle (unique muscle pulley system)
Describe the pectoral girdle in birds and its adaptation for flight ?
Bird pectoral girdle
Triangulated bones pectoral girdle = acts to stabilise the cranial thorax (Notarium)
The pectoral girdle is composed of three bones
Coracoid - very strong articulates to the sternum
Scapular - tightly bound to the rib cage
Clavicle - fused in the midline (Furcula or wish bone)
The pectoral girdle forms a stable suuport for the wings. The humerus articulates with the scapular and coracoid at the Glenoid fossa.
Disscuss why the neck of birds is so flexible?
The flexability of bird necks
The neck of birds
- one occipital condyle
- multiple cervical vertebrae 8-25 (only 7 in mammals)
- All cervical vertebrae carry cervical ribs, as a caudal spike at the transverse process
- have articular joints making them very flexible
(NO FIBROCARTILAGE DISCS)
Explain why the thorax in birds is fused?
What is this fused thorax called?
Birds’ Notarium = fused vertebrae
- The fused vertebrae of the thorax is to support the powerful flight muscles
- T1 = first sternal rib
- Ribs are reinforced to transfer loads (uncinate processes attached scapular muscles to strengthen the rib cage).
How is the sternum important for flight in birds?
Describe how the muscles and tendons act for flight in birds?
The mechanism of flight in birds
/ a pulley system
Foramen triosseum = the junction between the clavicle, coracoid and scapular - passage for the tendon of the supracoracoides. muscle
Pectoralis muscle
superficial down beat
very large cross sectional area
attaches ventrally to the humerus
Supracoracoides M.
Deep up beat
Smaller cross sectional area
attaches dorsally to the humerus
Which sites on a bird are most suitable for injection or blood removal?
Avian injection sites
Intramuscular injections
- pectoralis muscle
Blood removal
- cutaneous ulnar (wing vein) preferable
Describe the adaptation of the pectoral appendicular skeleton in birds for flight?
Pectoral appendicular skeleton
Fusions of the bone in the wing
This acts to
- reduce muscle weight
- restrct the range of movement
- reciporacal apparatus
How
Fused carpometacarpus
- there is only two free carpal bones; the others are fused to the metacarpus
- the digits are reduced but this varies between different species
Describe the thoracic movement during respiration in birds ?
Describe the caudal axial fusions which occur in avian species?
Describe the modification of the hindlimb in birds for the purpose of flight ?
Hind limb fusion
Tibiotarsus
The tibia and the proximal row of the tarsus is fused
The is located between the proximal and distal tarsal bones
Tarsometatarsus
The distal row and metatarsal bones are fused
Define the pneumatic bones and how they are beneficial to birds?
What is the perching mechanism in birds ?
The perching mechanism
Key = the digital flexor tendon runs caudally to the tarsal joint before running to each digit.
This enables the bird to stay on a branch with minimal muscular effort
- when the bird lands on a branch its body weight forces flexion of the tarsus pushing down on the branch and tendon of the flexor muscles
- the effect is to flex all the digits which automatically grip the branch
Define a brood patch in birds ?
Describe the location and function of the Uropygial gland in birds ?
Describe the structure of a feather; including barbules, hooklets and the calamus?
In birds what is the Pterylae and Apteria?
Describe contour and filoplume feathers ?
6 primary differences
Describe how the respiratory system of birds is different to that of mammals ?
The respiratory system of birds differs from those of mammals by a number of very specific features
1. No vocal cords (syrinx which is the organ of voice production)
2. Complete tracheal rings
3. No diaphragm (no seperation between the thoracic and abdominal areas)
4. Unidirectional air flow (efficiency)
5. Pneumatic bones (extension of air sacs)
6. Sternal hinge (no lateral rib cage expansion)
Describe the role of the nasal cavity in birds?
The role of the nasal cavity in birds
- olfactory function
- particle filtering/ infiltration
- water economy
- heat exchange
The recover of exhaled saturated water vapour is crucial in arid zines or migratory birds. (may recover 50-70% of water in inhaled air 20-30 degrees)
Identify the infraorbital sinus of the head in birds ?
Infraorbital sinus
Fills the hollow space within the skull - opens into the nasal cavity and caudal nasal choncae
- olfactory function
- it is a paranasal sinus (maxillary) produces mucous
- open space under the skin in the lateral region of the upper jaw
- common site for infection with respiratory bacteria and viral pathogens
Describe the location of the syrinx and its function in birds ?
Describe the location and function of nasal salt glands in birds ?